Method of attaching annular elements to supporting structures



Oct. 11, 1932. NELSON 1,881,867

METHOD OF ATTACHING ANNULAR ELEMENTS TO SUPPORTING STRUCTURES Filed p 2. 1930 2 Sheets-Sheet 1 INVENTOR.

A TTORNE Y.

Oct. 11, 1932. A. M. NELSON 1,881,867

METHOD OF ATTACHING ANNULAR ELEMENTS T0 SUPPORTING STRUCTURES Filed Sept. 22, 19:50 2 Sheets-Sheet 2 INVENTOR.

BY W v M A TTORNE Y.

Patented Get. 11, 1932 Lauren STATES r'rEN- orrica i ALFRED M. NELSON, 0F MILWAUKEE, WISCONSIN,'ASSIGNOR TO 'iHE VILTER MANUFAC TUBING COMPANY, OF MILWAUKEE, WIS

GONSIN, A COREOBATION OF WISCONSIN Application filed September 22, 1930; Serial No. 4%,740.

The present invention relates in general to an improved method of attaching annular elements to supporting structures, and relates more specifically to an improved process of rigidly fastening the ends of tubes to tube-sheets and to improved mechanism for effecting such fastening.

An object of the invention is to provide a new and useful method for efiecting rigid attachment of. one element to another.

It has heretofore been common commercial practice in the boiler, condenser, and refrigeration industries, to attach the end of each of a bank of tubes to an adj acent tube sheet, by inserting the tube end into a hole formed in the sheet and by. subsequently expanding the inserted tube end into intimate contact with the bounding surface of thereceiving hole.

It has also been customary in some cases to cut an annular groove of greater diameter than that of the hole itself, intermediate the ends of each hole, and to subsequently expand the tube into this groove in order to prevent axial displacement of the tube relative to the sheet. With this prior construction, a groove was left within the, tube adj acent to the groove in the sheet, such grooves being objectionable inthat they tend to accumulate dirt and prevent ready cleaning of the interior of the tubes. The tube-receiving holes are formed by drilling through the sheet, and in the prior groovedconstruction the grooves were formed by cutting away the metal, the tube ends being expanded into direct engagement with the surfaces of the finished holes and grooves, with the aid of a rotary expander cooperable with the interior of the tube ends.

In order to prevent accumulation of dirt within the tube ends and to permit ready cleaning of the tubes, it is desirable to avoid internal grooving of the tube ends as in the prior construction wherein grooves were provided between the ends of the holes. The drilling of these holes and the cutting of the: grooves to accurate diameter, has also introduced frequent breakage of drills and of the grooving tools, and the prior construction did not provide leak-proof final unions.

A more specific objec't of the present in vention is to provide an improved method of securing a more rigid and tighter union between a tube and a supporting tube-sheet,

While retaining all of the advantages of the prior constructions. In accordance withthe improvement the metal adjoining the tube; receiving holes of the'tube-sheets,'is com pressed byproviding one ormore rollediannular grooves therein, the tube ends being subsequently expanded to fill theseannular grooves while avoiding the formation'of depressions in the interiors of the tube ends.- This produces a fastening in which the metal at the tube ends, as well as in the adjacent portions of the tube-sheet, is" properly condig tioned to resist destruction of the joint, and wherein the tube is effectively locked against longitudinal displacement relative to itssupport. The invention further contemplates improved 'mechanism for facilitating/Commercial exploitation of the improved process by quickly and effectively rolling the grooves in the support preparatory to final fasten ing of the elements and without-breakage of tools.

A clear conception of the several steps of the improved process and of the construction. and mode of manipulating several forms of the improved mechanisms during commercial exploitation of the process, may be had by referring to the drawingsaccompanying and forming a part of this specification, in" which like reference characters designate the same or similar parts in the various views:

Fig. 1 is a part-sectional side elevation of oneforml of tool for conditioning the holes in a tube-sheet preparatory to attaching the ends of the tubes thereto, i Q

Fig. 2 is a transverse section throughthe tool disclosed in'Fig. 1, the section being taken along the line 2-2 ofFig. 1 looking in j i the direction of the arrows; v j

Fig. 3 is a part sectional side elevation of another type of tool for conditioning .the holes'in tube-sheets preparatory to attaching the line 44 of Fig. 3 looking in the direction of the arrows;

Fig. 5 is a part-sectional side elevation of still another form of tool for conditioning the holes in tube-sheets preparatory to the fastening of tuhes'thereto; 3

Fig. 6 is a transverse section through the tool of Fig. 5, the section being taken along theline 6-6 of Fig. 5 looking inthe direction of the arrows;

Fig. 7 is an enlarged sectional view throughthe end of a tube attached to a fragment of,

a tube-sheet, the hole'within the tube sheet having been conditioned with a tool of the. form shown either in Fig. 1 or Fig. 5

Fig. 8 is a similarly enlarged section through the end of a tube and through a fragment of a'tube-sh-eet, wherein thefastening has been effected Wltil the .aid of a tool such as shown in Fig. 3; and

Fig. 9 is a fragmentary section through the portion of the implement adjoining the chamfered driving pins. I

Referring specifically to Figs. 1 and 2,,the improved groove-rolling implement shown therein, comprises in general a cage member lOhavingone or more elongated radiating recesses 13 of substantially circular cross-section; a roller 11 frcelyrotatably supported in each of the recesses 13;. and a spindle 14 having a tapered portion 23 cooperable with the rollers 11 to urge the latter'outwardly and to simultaneously rotate the rollers during rotation andl-ongitudina'l advancement ofthe spindle 14. V

Each of the rollers 11 is of substantially cylindrical formation, enlarged medial portion 12 adapted to coact directly with thetapered portion 23 of the spindle 14, and the corresponding ends of w the rollers 11 are adapted to coact with thrust of the recesses. 9:

blocks 32mounted in the cage member at the correspondingjends of the recesses 13. While the recesses 13 are formed to permit free rotation and limited outward movement of. the rollers ,11 therein, the outermo t portionsof these recesses 13 are constricted so as to prevent the rollers from falling out The rollers 11 are insertable endwise into the recesses 13, through openings 22, and a retaining cap 20 secured to the end of the cage member 10 by means of screws 21, serves to prevent excessive endwise-movement of the rollers away from the thrust blocks 32. The peripheral portion of the cage member 10 adjacent to the cap 20, is provide-d with a flange having a continuous groove 18 therein, and a bearing ringjl? coacts with.

. the outer and side portion of this fla 'e and b carries aseries of radial set-screws 19 which extend into the groove 18 in order to hold the ring 17 in place while permittingfree rotation of the ring relative to the cage member 10.. The medial portion of the driving spindle 14' is provided with a stop collar spindle 14 except that it has an.

which may be locked in any desired position along the taper 23 by means of a set-screw 16, and the end of the spindle beyond the taper 23 is provided with a square shank 24 for imparting rotation thereto.

Referring specifically to Figs. 3 and 4, the modified groove-rolling implement shown therein is somewhat similar to that previously described, comprising in general a cage member 10 having" one or more radiating" recesses 13 of substantially circular cros the recesses 13 are formed to permit free rotation and limited outward movement of the rollers 11, the outermost portions ofthe' recesses 13 are likewise constricted to prevent the rollers from falling out of the recesses. The rollers '11 areinsertable endwise into the recesses 13 through openings 22, and a retaining-cap secured to the end of the cage memberIO" by means of screws 21, again serves to prevent excessive endwise movement of the rollers within the recesses 13. The peripheral portion of the cage member 10 adjacent to thecap 20, is provided with a flange having a continuous groove 1-8 therein, and a bearing ring l7 coacts with this flange and carries a series of set-screws 19 which extend into groove 18 for the purpose of holding the ring 17 in place, while permitting free rotation of this ring relative to the cage member 10. The medial portion of the driving spindle 14 is likewise provided with a stop collar 15 having a setscrew 16 for the purpose of locking the collar in various positions of adjustment along the taper 23, andthe endof the spindle 14 is also provided parting rotation thereto. I

During normal operation of the implement illustratediii-Figs. 1 to 4 inclusive, the tubev sheet 25 to which the tubes 47 are to be fastened, is provided withdrilled' holes erly spaced and positioned. These drilled holes 26 are of slightly greater diameter than the outer diameters of the tubes 47 which are to coact therewith. Either of the implements of Figs. 1 0123 may be utilized for the purpose of grooving and of simultaneously compress ing the metal at the holes 26, the implement of Fig. 1 being adaptedto form a single groove in each hole 26 intermediate its endsa-nd the implement with a square sha k 9,4 f j grooves in each of the vided of Fig. 3 being adapted to compress a plurality of grooves intoeach of the holes 26.

been inserted within one of the holes 26 and the bearing collar 17, 17 thereof has been provided with an abundance of lubrication and has been brought into contact with the face of the sheet 25, rapid rotation may be imparted to the spindle 14, 14 which may be simultaneously urged into the space between the rollers 11, 11. The collar 15 may be set to limit the longitudinal movement of the spindle, so that when the spindle. has been advanced to the position where the collar 15 engages the adjacent cap 20, the formation of the grooves within theholes 26 and the compression of the metal bounding the holes, has been completed. As the rapidly.

rotating portion 23 of the spindle advances longitudinally between the rollers 11, 11, the rollers are simultaneously rapidly rotated and forced outwardly within their radial confining recesses 13, 13 thus rolling the grooves and simultaneously compressing the metal within and adjoining the rolled grooves. The bearing ring 17 17 serves to permit free rotation of the cage 10, 10 during the rolling operation, while creating minimum resistance to such rotation of the cage member. When therolling operation has been completed, the spindle 14, 14 may be withdrawn and the rollers 11, 11 will then'recede into the recesses 13, 13 and will permit free withdrawal of the cage member 10, 10- from the finished hole 26.

Referring specifically to Figs. 5 to 9, the improved groove-rolling implement shown therein, is of somewhat different construction and operates in a slightly different manner, from the implements shown in Figs. 1 to 4 inclusive. The modified implement of Fig. 5 comprises in general a cage 33 having one or more radiating recesses 31 of substantially circular cross-section; a roller 28 freely rotatably supported in each of the recesses 31; and a spindle 34 having a tapered end portion 37 cooperable with tapered end portions 29 of the rollers 28, to urge these rollers outwardly and to simultaneously rotate the same during rotation and longitudinal advancement of the spindle 34.

Each of the rollers 28 besides having the tapered end portions 29, has a medial enlarged portion 30, the spindle 34 being prowith a recess 38 for permitting rotation and longitudinal displacement of the spindle without engagement thereof with the roller enlargements 30. The larger ends of the rollers 28 are adapted to coact with thrust blocks 32 mounted in the cage member 33 at the corresponding ends of the recesses 31. While the recesses 31 are formed to permit free rotation and limited radial displacement of the rollers 28 therein, the outermost portions of the recesses are constricted to preventithe rollers from falling 'out' of the rerecesses31"through-the central opening in the cage member 33, when the spindle 34 has been removed, and are retained within the recesses by the spindlea'fter insertion thereof The cage 33isfprovided with a threaded flange to which a spring housing39 is directly: attached, and this flange isprovided with a chamfercd pin'44 extending parallel cesses. The rollers 28 are insertable into the After the'roller-supporting cage 10,10 has to the spindle 34. Thebearingv ring 27 is secured to the casing 39 adjacent to the cage member 33 by meansof set-screws 46, and thisbearing ring coacts with the fiangeat the end of the cage member 33. The spindle 34 isprovided with a threaded portion 36 and has a square driving shanlr 45la-t the end thereof, and apush member 35 .coacts with the .threaded portion 36 and is adapted to".

ridetherealong. The endof the push mem ber 35 adjacent the'cagemember33 is like wise provided with a chamfered pin 43 adapted to coact with'thepin 44 under certain conditions of operation. A relatively stiff compression spring40 coacts witha roller bearing 41 interposed between one end of the spring and theflange on the member 35, and the opposite end of the. spring 40 re: acts against an end ring 42. secured. to the end ofthehousing 39; a 2

During normal operationof the implement illustratedin Figs.j5, 6 and 9, thetube-sheet 25 to which thetubes47' are to be attached, is provided as beforewith. drilled'holes 2.6 properly spaced and positioned and of slightly greater diameter than the external diameters of the ends of the tubes 47. The rolleresupporting cage 33 after havingbeen inserted in one of the llOlQS'QG as shown in I Fig. 5, engages one sideof the bearing ring 27, the other side of which is in direct engagement with the outer" face of the tubesheet 25. The rollers and thevarious bearings should be supplied with an abundance of "lubrication, whereupon relativelyrapid rotation may be imparted to the spindle 34 through the shank 45. As the spindle 34 rotates, the screw-threads coacting with the push member 35, cause the spindle to slowly travel forwardly between the rollers 28, therebysimultaneously rotating these rollers and forcing them outwardly against the wall of the hole 26. The rollers 28 are driven virtue of the coaction between the taper 37 of the spindle 34 with the tapered end portions 29 of the rollers, and'as the rollers 28 are forced. outwardly, theieiilargements 30 thereof simultaneously form a groove in the medial portion of the hole 26by compressing the metal of thetube-sheet 25. During the relativerapid rotation of the spindle 34, the cage member 33 is slowly rotated and the chamfered pin 44 engages the pin 43 carried by the push member 35 andcauses similar slow rotation of the member and of the spring V When the groove has been formed, re-

verserotation of the spindle 34 willwi-thdraw vthe taper 37 from the space between the rollers28, and the pin 43 is then swung about the axis of the spindle 34 and impinges against the opposite side of the pin 44 thus imparting a blow and subsequent reverse rotat-ion to the cage 33,.Wl'1i6l1 quickly releases the rollers 28 from the formed groove and permits withdrawal of the implement from the tube-sheet." a

- After the grooves have thus been rolled into the holes 26 of the tube-sheet 25, the tubes 47 may be finally fastened to the sheet 25. The end of each tube 47 is inserted within a groovedhole 26, and a rolling device is then applied within the tube end 48, and this end is expanded as indicated in Figs. 7 and 8 to snugly coact with the wall of the hole 26 and a with the grooves or 51 formed in the tubesheet. The compression of the metal in the tube end by rolling is continued until the grooves are entirely filled with metal and the extreme end 49 of the tube is rolled out to form a. slight flange which assists the enlargement coacting with the grooves 50 or 51, in positively preventing endwisedisplacement of the tube. In Fig. 7, the single groove 50 has been formed with an implement of the type shown in Fig. 1 or Fig. 5, and in Fig. 8 the grooves 51 have been formed withan im plement of the type shown in Fig. 3. V

' From the foregoing description it will be apparent that the present invention provides a simple and highly effective method of fastening tubes to tu'be sheets, without danger of breakage of cutting tools such as formerly'used to provide the grooves. The holes 26 may be formed by an ordinary drilling operation, and the rolled grooves 50, 51 being formed by compression of the metal, provide perfect seatings for the tube ends and eliminate possible leakage of fluids past the joints.

Therolled groovescan also be formed much quicker than the cut grooves, and commercial exploitation of the present improved process has resulted in the production of superior fastenings in much less time than has heretofore been possible. The final fastenings are also devoid of internal grooves within the tube ends, thereby facilitating cleaning of the tubes 47 Itshould be understood that it is not desired to limit the invention to the exact steps of. the improved method herein shown and 7 described, for various modifications within the scope of the claims may occur to persons skilled in the art.

What I claim as my invention is:

1. The method of attaching a tube to a sheet, which comprises forming in the sheet a hole havinga diameter approximating that of the exterior of the tube, enlarging the diameter of part of the holeto' form a groove and compressing the bounding wall of the hole and groove, inserting thetube end with? in the hole, and expanding the tube end into intimate contact with said compressedwall of the hole and groove. i

2. The method of attaching a-tube to in. the hole, and expanding the tube end into intimate contact with saidcompressed wall and groove while avoiding complementary grooving of. the interior of the tube end.

3. The method of attaching a tube to. a 7

sheet, which comprises forming in: the sheet a hole having a uniform diameter approximating that of the exterior of the tube, enlarging the diameter of part of the hole by compressing the bounding wall to form a series of. local annular grooves therein and also compressing the bounding wall of the hole adjoiningsaid grooves, inserting the tube end within the hole, and expanding the tube end into intimate contact with said compressed wall and grooves while avoiding complementary grooving ofthe interior of the-tube end. In testimony whereof, I afi'ixmy. signature.

' ALFRED M. NELSON. 

